• Macromolecular Research
• /
• v.12 no.4
• /
• pp.399-406
• /
• 2004

Glass-like carbon precursors shrink significantly during curing and carbonization, which leads to crack formation and bending. Cured furan resin powder and ethanol were added to furan resin to diminish the weight loss, to suppress the shrinkage and bending, and to readily release the gases evolved during polymerization and curing. Curing and carbonization were controlled by pressure and slow heating to avoid damage to the samples. The effect of the filler and ethanol on the fabrication process was examined by measuring the properties of the glass-like carbon, such as the specific gravity, bending strength, electrical resistivity, and microstructural change. The specific gravities of the filler-added glass-like carbons were higher than those of the ethanol-added samples because of the formation of macropores from the vaporization of ethanol during the curing and polymerization processes. Although the ethanol-added glass-like carbons exhibited lower bending strengths after carbonization than did the filler-added samples, the opposite result was observed after aging at 2,600$^{\circ}C$. We found that the macropores created from ethanol were contracted and removed upon heat treatment. The electrical resistivity of the glass-like carbon aged at 2,600$^{\circ}C$ was lower than those of the samples carbonized at 1,000$^{\circ}C$. We attribute this phenomenon to the fact that aging at high temperature led to well-developed microstructures, the removal of macropores, and the reduction of the surface area.

• Journal of the East Asian Society of Dietary Life
• /
• v.15 no.6
• /
• pp.728-737
• /
• 2005

This study was conducted to evaluate the physicochemical characteristics of pound cake made of substituted flour with different amount of $\beta-glucan$ i.e. 3, 6 and $9\%$ respectively. $\beta-glucan$ is a functional food material produced from Agrobacterium sup. R259 KCTC 10197BP. The specific gravity and pH of dough were found to be increased according to $\beta-glucan$ content Rheological property such as adhesiveness of dough has no difference between control and $\beta-glucan$ added groups. The pH of baked pound cake was not significantly different between control and $\beta-glucan$ groups. The volume of baked pound cake wag not significantly different between control and the ones with up to $6\%$ $\beta-glucan$, Lightness (L), redness (a) and yellowness (b) value of Hunter color system of cake crumb were not significantly different among teated groups, except a value of crust in $9\%$ $\beta-glucan$ group. the moisture content of cake increased according to $\beta-glucan$ content. Hardness by texture analyser was decreased with increasing $\beta-glucan$ content although cohesiveness wag not changed in β$\beta-glucan$ groups, compared with the control. Sensory evaluation results showed that the mean scores of over·all acceptability in 3 and $6\%$ $\beta-glucan$ were higher than that of control. Based on these results, the addition of $\beta-glucan$ to pound cake up to $6\%$ was considered to be desirable especially in terms of texture.

• The KSFM Journal of Fluid Machinery
• /
• v.20 no.1
• /
• pp.53-58
• /
• 2017

This paper describes liquidity evaluation on the horizontal branch pipe connected to a food waste disposer and performance of five disposers marketed. Experimental apparatus for analyzing the five disposers has been introduced to measure vibration, sound level and power consumption of the disposers. Simulator for analyzing the required water velocity to avoid waste jam inside the pipe connected to a food waste disposer has been designed and constructed. The simulator can control some experimental parameters: pipe slope, disposer supply water quantity, food waste materials and operation time of a disposer. Throughout the experimental measurements of the disposers marketed, it is found that the time need to crash food waste is about 20 seconds on the average. At the same flow condition, increase rate of internal water velocity is accelerated as the pipe slope increases. The water velocity inside the pipe having 50 A and slope of 1/50 is 0.26 m/s when the water flowrate to supply the disposer is 16 l pm. Considering the specific gravity and adhesion property of food waste, water velocity of the horizontal branch pipe connected to a food waste disposer need to excess 0.26 m/s at least to avoid the waste blockage inside the pipe.

• Korean journal of food and cookery science
• /
• v.31 no.5
• /
• pp.642-651
• /
• 2015

Asparagus, which was known to be a good source of dietary fiber and vitamins, has been reported to possess various medical actions such as antioxidant and blood pressure regulating effects. In order to examine the quality and antioxidant characteristics of asparagus, asparagus sponge cakes were prepared with different ratios of freeze dried asparagus powder (0%, 2%, 4%, 6%, 8%, w/w) in this study. With the increase of asparagus powder content in the sponge cakes, the specific gravity and baking loss increased while the dough yield decreased significantly. The moisture contents of the sponge cakes were not significantly different between the control and the cakes prepared with asparagus powder. The pH of the sponge cakes decreased significantly with increased amounts of asparagus powder. Furthermore, the pH of the sponge cake containing 8% asparagus powder was the lowest at 7.49. With the increase of asparagus powder content in the sponge cakes, lightness (L) and redness (a) decreased, whereas yellowness (b) increased. In texture analysis, the hardness and chewiness of the sponge cakes increased as the asparagus powder content increased, while the cohesiveness of the sponge cakes with asparagus powder decreased. Both total polyphenol content and DPPH (1,1-diphenyl-2-picryl hydrazyl) radical scavenging activity increased significantly with increased levels of asparagus powder content in the sponge cakes. In a sensory evaluation using a scale of 1-7, the sponge cake containing 8% asparagus powder had the lowest sensory preference scores. Therefore, the results of this study suggest that sponge cake prepared with 6% asparagus powder is the most appropriate product for quality characteristics.

• The Journal of the Petrological Society of Korea
• /
• v.6 no.1
• /
• pp.34-44
• /
• 1997

The Jurassic granites, commercially called Yangu stone in the Pocheon-Euijeongbu area, have generally compact and coarse-grained textures, which could be classified into two types; grey granite(Gg) and light pink granite(Gp). Specific gravity, absorption ratio and prosity of Gg and Gp in physical property are 2.64 and 2.61, 0.32 % and 0.44 %, 0.86% and 1.13 %, respectively. These higher values of two latters of Gp than those of Gg are due to the more abundant microcracks in Gp. Compressive strength og Gg than those of Gg are due to more abundant microcracks in Gp. Compressive strength og Gg and Gp are 1,726 kg/cm2 and 1,717 kg/cm, respectively and bestrength has a positive proportion with Qz+Af+Pl(quartz+alkali feldspar+plagioclase) modes without trending with Bt+Ac(biotite+accessories). Tensile strength has the positive proportions with Qz+Af+Pl and Bt+Ac. While Bt+Ac has a negative trend with abrasive hardness, Qz+A+Pl shows a positive one. These may suggest Qz+Af+Pl mainly affects on strenghts potentional dimension stone than Gp.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09c
• /
• pp.129-134
• /
• 2010

This paper investigates effects of rubber inclusion on the strength and physical characteristics of rubber.added composite geomaterial (CGM) in which dredged soils, crumb rubber, and bottom ash are reused for recycling. Several series of test specimens were prepared at 5 different percentages of rubber content (i.e. 0%, 25%, 50%, 75%, and 100% by weight of the dry dredged soil) and three different percentages of bottom ash content (i.e. 0%, 50% and 100% by weight of the dry dredged soil). The mixed soil specimens were subjected to unconfined compression test and elastic wave test to investigate their unconfined compressive strengths and small strain properties. The values of bulk unit weight of the CGM with bottom ash content of 0% and 100% decrease from 14kN/$m^3$ to 11kN/$m^3$ and 15kN/$m^3$ to 12kN/$m^3$, respectively, as rubber content increases, because the rubber had a specific gravity of 1.13. The test results indicated that the rubber content and bottom ash content were found to influence the strength and stress-strain behavior of CGM. Overall, the unconfined compressive strength, and shear modulus were found to decrease with increasing rubber content. Among the samples tested in this study, those with a lower rubber content exhibited sand-like behavior and a higher shear modulus. Samples with a higher rubber content exhibited rubber-like behavior and a lower shear modulus. The CGM with 100% bottom ash could be used as alternative backfill material better than CGM with 0% bottom ash. The results of elastic wave tests indicate that the higher rubber content, the lower shear modulus (G).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.2775-2784
• /
• 2013

A bead is intended to reach a specified target point in the minimum-time when it travels along a certain curve on a vertical plane with the gravity. This is called the brachistochrone problem. Its minimum-time control input may be found using the calculus of variation. However, the accuracy of its minimum-time control input is not high since the solution of the control input is based on a table form of inverse relations for some complicated nonlinear equations. To enhance the accuracy, this paper employs the neural network to represent the inverse relation of the complicated nonlinear equations. The accurate minimum-time control is possible with the interpolation property of the neural network. For various final target points, we have found that the proposed method is superior to the conventional ones through the computer simulations.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.9
• /
• pp.3802-3807
• /
• 2011

In this study, in-plane and out-plane compression tests of aluminum foam and honeycomb sandwich composites were carried out. Through these tests, the relationships of load-displacements were analyzed and the compression characteristics were compared with each other. The specimens were compressed with the speed of 1mm/min by using the universal testing machine. Experimental procedures were taken with photograph by the camera and load cell data were stored into computer. Test results showed that buckling was occurred at the aluminum foam core and honeycomb core according to the increase of load. In the in-plane compression test, the maximum load of aluminum foam specimen was similar with that of honeycomb sandwich. The property of honeycomb was better than that of the foam in consideration of specific gravity. In the out-plane compression test, compression maximum load of aluminum honeycomb sandwich composite was higher than that of aluminum foam sandwich composite.

• Resources Recycling
• /
• v.26 no.5
• /
• pp.48-53
• /
• 2017

During steelmaking on EAF, 1 ~ 2% of dust is generated. EAF Dust contains 20 ~ 30% of Zn and Fe. Dust contained in Off-gas is passed through combustion tower and cooling tower, and then captured in bag filter. About 15 wt.% of dust is dropped at the bottom of Combustion tower by its specific gravity, which was also carried out to recycle company with more higher charge than Bag filter dust. This study is focused on the combustion tower dust, and seperation as a function of operation period and particle size. As a result, Zn and Fe content of dust is more affected by size factor than operation period.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.4
• /
• pp.255-261
• /
• 2015

Soil catena can be characterized by some properties, such as drainage levels and soil textures. Characteristics of soil catena are different drainage levels from a summit to the direction of gravity and similar soil textures. Therefore this study was performed GIS (Geographic information system) and statistical analyses using perimeters from soil series in order to characterize quantitatively and objectively soil distributional properties in Korea. The total of 16 soil series from representative granite and granite gneiss originated soils were selected among inland soils from detailed soil maps (1:25,000 scale) in Rural Development Administration (RDA) and analyzed. After the detailed soil maps were merged by soil series unit, perimeters were measured from one soil series to neighboring soil series using functions of table join, merge, dissolve, buffer, and clip in ArcGIS (10.1). The covering ratio of each soil series unit was calculated from neighboring perimeters by soil series and applied to clustering analysis. Soils that were analyzed were the total of 16 soil series; 7 of sandy loam and 9 of clay loam. As a result, analyzed soil series adjoined complicatedly such as Hyocheon series adjoined 26 series and Jisan did 276 series. The results of the clustering analysis showed that soils were clustered by soil textures except a few soil series. This study applied only one property that was a length of neighboring soil series to GIS and statistical analyses. These results were compared to existing soil groups that were classified by new-soil taxonomy, texture, soil type and drainage level. It showed that these analyses can provide soil characteristics by soil texture. Based on this study, there is a need to investigate further objectively and quantitatively in statistical analyses of soil series.